In recent years, with the development of economy and society, more and more detections are required. Developments in material science, manufacturing technology, and microelectronics have spurred the advancement and widespread use of chip technology. Detection methods using chips, in particular, biochips, can greatly reduce the cost of medical testing and have extra advantages such as high-throughput, easy-integration. Typically, how to determine the type of detection units fast and accurately is required and necessary. The type of detection units can include the kind of analytes being analyzed in the units.
The traditional method for reading assay-information includes instrument reading, manual identification and barcode reading. However, instrument reading costs too much because of expensive equipment. Manual identification can be a waste of time and the cost of human labor is high. The printing of barcodes is complex and manufacturing the barcoded devices requires accuracy. In addition, reading a barcode requires detection of the boundaries and width of the barcode, and therefore requires high accuracy. In traditional methods, untested units should be detected one by one in proper order when there are severe different units on a chip, and requires moving the chip relative to a detector. The actual distance of the chip movement can be greater or less than designed; once the chip is moved by the wrong or inaccurate distance relative to the detector, the order of units can be changed. For example, one or more units can be skipped, which will cause incorrect identification of subsequent units. As a result, the results can be seriously deviated. Moreover, there is need for non-sequential detection, and the currently available technologies do not serve the need well.